Why does my battery keep draining?

I have a 1994 Chvy suburban with a 454 in it. I have replaced the battery but have to jump it in the morning everyday. It stays running and charged so i dont beleive it to be the alternator. It starts back up after it sits for awhile also. But when it sits overnight its dead. Also, sometime the starter squeels real loud when i try to start it. do you think the starter is going bad and its draing the battery at extended periods of time. Thanks for the advice